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![]() "Tam/WB2TT" wrote in message ... John, I had breakfast with some friends this morning. One of them has a PHD in EE, specializing in antenna design. He thinks the antenna should work, but suggested changing the spacing between the upper and lower conductors. He also told me to look for multiple resonances. I just now tried that, with the spacing essentially 0. What I got was a new resonance at 165 MHz, with Z=18 + j0. . Interestingly, I now seem to have hit parallel resonance, like you did, and R goes down either side of 165. In fact, accross 100 -150 MHz the Z is 0 -jX. When I was messing around with spacing, at one time I got 202 + j0 at 129 MHz; but that is way off calculated frequency. I probably should not be doing this inside, as it is not entirely repeatable. I also tried a longer piece of coax (RG8X, Vp=.75) that gave me a 5 foot folded dipole. That should be resonant at about 93 MHz. I clearly got multiple resonances: F R X 92.5 3 j3 100 11 j44 110 80 j181 120 4 j30 127 4 j1 160 53 j14 SWR=1.3 170 11 j0 The feedline was also 5 feet, since I did not know what a wavelengt was going to be. This looks like it wants to be a 160 MHz antenna, instead of 93. Lastly, I tried the 5 foot antennawith a 2 inch feedline.Resonance was at 156 MHz. If I get a chance, I will try it outdoors tomorrow. Tam/WB2TT Thanks for the hard work, Tam. I'm not sure I know what to make of all this, but it appears that the antenna is not what I thought it would be. Thanks again. John |
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